U.S. patent application number 14/748465 was filed with the patent office on 2016-11-03 for bondline control fixture and method of affixing first and second components.
The applicant listed for this patent is International Business Machines Corporation. Invention is credited to Tymon Barwicz, Nicolas Boyer, Paul Fortier, Stephane Harel, Roch Thivierge.
Application Number | 20160318241 14/748465 |
Document ID | / |
Family ID | 57204567 |
Filed Date | 2016-11-03 |
United States Patent
Application |
20160318241 |
Kind Code |
A1 |
Barwicz; Tymon ; et
al. |
November 3, 2016 |
BONDLINE CONTROL FIXTURE AND METHOD OF AFFIXING FIRST AND SECOND
COMPONENTS
Abstract
A bondline control fixture and an active bondline control
fixture are provided for affixing first and second components. The
bondline control fixture includes a base fixable relative to a
first component maneuvering device and comprising a first body
defining an aperture and a first chamber and a second body
disposable within the first chamber and defining a second chamber,
a flexible membrane disposable to seal the second chamber, a mobile
plate to which the second component is removably attachable, the
mobile plate being disposable in contact with the flexible membrane
and a pressure regulating system coupled to the second body and
configured to regulate a pressure within the second chamber to
deform the flexible membrane.
Inventors: |
Barwicz; Tymon; (Yorktown
Heights, NY) ; Boyer; Nicolas; (Quebec, CA) ;
Fortier; Paul; (Quebec, CA) ; Harel; Stephane;
(Quebec, CA) ; Thivierge; Roch; (Quebec,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Family ID: |
57204567 |
Appl. No.: |
14/748465 |
Filed: |
June 24, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14700738 |
Apr 30, 2015 |
|
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14748465 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/12004 20130101;
G02B 6/12 20130101; G02B 6/30 20130101; B29C 66/9221 20130101; B29C
66/9231 20130101; B29D 11/00663 20130101; B29C 66/8322 20130101;
B29C 66/1122 20130101; B29C 66/863 20130101; B29C 65/7847 20130101;
B29C 65/483 20130101; B29C 66/8242 20130101; B29D 11/00721
20130101; B29C 66/82421 20130101; B29C 66/8163 20130101; B29L
2031/3425 20130101; B29C 66/474 20130101 |
International
Class: |
B29C 65/48 20060101
B29C065/48; B29C 65/00 20060101 B29C065/00 |
Claims
1. A method of operating a bondline control fixture for affixing
first and second components, the method comprising: fixing a base
comprising a first body defining an aperture and a first chamber
and a second body defining a second chamber relative to a first
component maneuvering device; disposing the second body within the
first chamber; sealing the second chamber with a flexible membrane;
removably attaching the second component to a mobile plate with the
mobile plate contacting the flexible membrane; and coupling a
pressure regulating system to the second body and configuring the
pressure regulating system to regulate a pressure within the second
chamber to deform the flexible membrane.
2. The method according to claim 1, wherein the first component
comprises a flexible polymer component and the second component
comprises a photonic integrated circuit.
3. The method according to claim 1, wherein the first body
comprises sidewalls and a work surface supportable on the sidewalls
and the method further comprises defining a groove in communication
with the aperture.
4. The method according to claim 1, further comprising: interposing
a first section of the flexible membrane between the first and
second bodies; and hermetically sealing the second chamber with a
second section of the flexible membrane.
5. The method according to claim 1, wherein the flexible membrane
comprises rubberized material.
6. The method according to claim 1, further comprising sizing the
mobile plate to movably fit within the aperture.
7. The method according to claim 1, further comprising sizing the
mobile plate to rotatably fit within the aperture.
8. The method according to claim 1, further comprising vacuuming
the second component onto the mobile plate and dispensing adhesive
thereon.
9. A method of operating an active bondline control fixture for
affixing first and second components, the method comprising: fixing
a base defining an aperture and a chamber relative to a first
component maneuvering device; removably attaching the second
component to a mobile plate with the mobile plate disposed at least
partly in the aperture; and adjusting an attitude of the mobile
plate relative to the base in accordance with a degree of
parallelism between the first and second components.
10. The method according to claim 9, further comprising: disposing,
within the chamber, actuators coupled to the base and a local
portion of the mobile plate and configured to adjust a distance
between the base and the local portion; and controlling an
operation of each actuator in accordance with the degree of
parallelism.
11. The method according to claim 9, further comprising sizing the
mobile plate to movably fit within the aperture.
12. The method according to claim 9, further comprising sizing the
mobile plate to rotatably fit within the aperture.
13. A method of affixing first and second components, the method
comprising: supporting a mobile plate on a base fixable relative to
a first component maneuvering device; removably attaching the
second component to the mobile plate; dispensing adhesive on either
the first or second component; maneuvering the first component
toward the second component with the first component maneuvering
device; and manipulating the mobile plate to increase a degree of
parallelism between the first and second components.
14. The method according to claim 13, wherein the manipulating
comprises deforming a flexible membrane on which the mobile plate
is disposable.
15. The method according to claim 13, wherein the manipulating
comprises adjusting a distance between the mobile plate and the
base.
Description
[0001] This application is a continuation of U.S. application Ser.
No. 14/700,738, which was filed on Apr. 30, 2015. The entire
disclosures of U.S. application Ser. No. 14/700,738 are
incorporated herein by reference.
BACKGROUND
[0002] The present invention relates to assembly of
micro-electronics, opto-electronics and photo-electronics and, more
particularly, to a bondline control fixture, an active bondline
control fixture and a method of passively or actively affixing
first and second components.
[0003] In various technologies, there is frequently a need for
attaching two standard pick and place components together. In some
cases, the components may include a flexible polymer component with
a standard optical interface and polymer waveguides extending
outwardly from a side of the interface along a lower surface of a
compliant extension and a photonic integrated circuit (IC) with
photonic IC waveguides on an upper surface of a complementary
metal-oxide-semiconductor (CMOS) element. Previously, one of the
components has been picked up with a picker arm and placed on the
other component with that other component residing on a base. Both
the picker arm and the base may move in X-, Y- and Z-directions in
order to position the components with respect to each other.
[0004] However, no specific control is used to ensure that the
parallelism between the picker arm and base surfaces is tightly
controlled. In the case of the components being the flexible
polymer component and the photonic integrated circuit (IC), this
lack of parallelism impedes the enablement of an adiabatic coupling
of light signals from the polymer waveguides to the photonic IC
waveguides.
SUMMARY
[0005] According to an embodiment of the present invention, a
bondline control fixture for affixing first and second components
is provided. The bondline control fixture includes a base fixable
relative to a first component maneuvering device and comprising a
first body defining an aperture and a first chamber and a second
body disposable within the first chamber and defining a second
chamber, a flexible membrane disposable to seal the second chamber,
a mobile plate to which the second component is removably
attachable, the mobile plate being disposable in contact with the
flexible membrane and a pressure regulating system coupled to the
second body and configured to regulate a pressure within the second
chamber to deform the flexible membrane.
[0006] According to another embodiment, an active bondline control
fixture for affixing first and second components is provided and
includes a base fixable relative to a first component maneuvering
device, the base defining an aperture and a chamber, a mobile plate
to which the second component is removably attachable, the mobile
plate being disposable at least partly in the aperture and an
actively controllable actuation system configured to adjust an
altitude of the mobile plate relative to the base in accordance
with a degree of parallelism between the first and second
components.
[0007] According to yet another embodiment, a method of passively
or actively affixing first and second components is provided. The
method includes supporting a mobile plate on a base fixable
relative to a first component maneuvering device, removably
attaching the second component to the mobile plate, dispensing
adhesive on either the first or the second component, maneuvering
the first component toward the second component with the first
component maneuvering device and manipulating the mobile plate to
increase a degree of parallelism between the first and second
components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic side view of an apparatus in
accordance with embodiments;
[0009] FIG. 2 is a perspective view of a bondline control fixture
in accordance with embodiments;
[0010] FIG. 3 is a cutaway view of the bondline control fixture of
FIG. 2;
[0011] FIG. 4 is an enlarged side view of a portion of the bondline
control fixture of FIG. 3;
[0012] FIG. 5A is a side view of first and second components being
brought together in a non-parallel orientation;
[0013] FIG. 5B is a side view of the first and second components
being brought together in a parallel orientation;
[0014] FIG. 6A is a side view of first and second components being
brought together in a non-parallel orientation;
[0015] FIG. 6B is a side view of the first and second components
being brought together in the non-parallel orientation with a
flexible membrane being inflated;
[0016] FIG. 6C is a side view of the first and second components
being brought into contact in the non-parallel orientation with the
flexible membrane being inflated;
[0017] FIG. 6D is a side view of the first and second components in
contact in a parallel orientation with an inflated flexible
membrane being deformed;
[0018] FIG. 6E is a side view of the first and second components in
contact in the parallel orientation with the inflated flexible
membrane being further deformed; and
[0019] FIG. 7 is a side view of an active bondline control fixture
in accordance with embodiments.
DETAILED DESCRIPTION
[0020] As will be described below, a passive or active bondline
control fixture is provided for passively or actively increasing a
degree of parallelism between first and second pick and place
components, such as a flexible component with a standard optical
interface and polymer waveguides near the side of the interface
along a lower surface of a compliant extension and a photonic
integrated circuit (IC) with photonic IC waveguides near an upper
surface. The photonic IC could be a complementary
metal-oxide-semiconductor (CMOS) element. Use of the passive or
active bondline control fixture allows the first component to be
affixed to the second component so that efficient optical coupling
of light signals from the waveguides of the first component to the
photonic IC waveguides of the second component is enabled without
need for micro-adjustments of a picker arm of the first component.
Various light coupling schemes could be used such as adiabatic
coupling, directional, coupling or butt coupling.
[0021] With reference to FIG. 1, an apparatus 1 is provided for
bringing together and affixing to one another standard pick and
place fixtures such as a first component 2 and a second component
3. The apparatus 1 generally includes a picker arm 4 that is
configured to pick up and maneuver the first component 2 by way of
vacuum pressure and a base 5, which is fixed relative to ground and
the picker arm 4 and on which the second component 3 is mounted and
held by vacuum pressure. During operation, a tip 400 of the picker
arm 4 contacts the first component 2 and a vacuum 401 of the picker
arm 4 engages to permit the picker arm 4 to lift the first
component 2. The picker arm 4 then moves the first component 2 in
the X- and Y-directions until the first component 2 is positioned
over the second component 3. Next, the picker arm 4 moves the first
component 2 in the Z direction toward the second component 3 until
they come into contact. Upon contact, adhesive between the first
and second components 2 and 3 is permitted to cure.
[0022] In accordance with embodiments, the first component 2 may
be, for example, a flexible polymer component with a standard
optical fiber interface and polymer waveguides near the side of the
interface along a lower surface of a compliant extension. The
second component may be, for example, a photonic integrated circuit
(IC) with photonic IC waveguides on an upper surface. The photonic
IC can be a complementary metal-oxide-semiconductor (CMOS) element.
In affixing the first component 2 to the second component 3,
efficient coupling of light signals from the polymer waveguides of
the first component 2 to the photonic IC waveguides of the second
component 3 is enabled. However, achieving such an enabling
configuration requires that a distance or Z-gap between the first
and second components 2 and 3 be very small and well controlled
(e.g., less than two microns and preferably less than one micron
level) along a significant area of proximity between the first and
second components 2 and 3. This area includes notable extents of
waveguides placed at the surface or in proximity of the surface on
both the first and second components 2 and 3.
[0023] Thus, with reference to FIGS. 2-4, 5A and 5B and 6A-6E, a
bondline control fixture 10 is provided and is capable of making
and adjusting a parallelism of standard pick and place fixtures
(i.e., the first and second components 2 and 3 of FIG. 1) to the
tolerances needed to enable efficient coupling of the light signals
from waveguides of the first component 2 to the photonic IC
waveguides of the second component 3. To this end, the bondline
control fixture 10 includes a base 20, a flexible membrane 30 (see
FIGS. 3-5A and 5B), a mobile plate 40 and a pressure regulating
system 50 (see FIG. 3). The base 20 is fixable relative to ground
and a first component maneuvering device (i.e., the picker arm 4 of
FIG. 1) and includes a first body 21 and a second body 22.
[0024] The first body 21 may be generally volumetric with sidewalls
210 and an upper work surface 211 that is supported on the
sidewalls 210. The sidewalls 210 and the upper work surface 211
cooperatively define an aperture 212, a first chamber 213 and a
groove 214. The upper work surface 211 has an inwardly facing
surface 2110 and a flange 2111 that extends inwardly from an upper
portion of the inwardly facing surface 2110. The aperture 212 is
generally defined in a plane of the upper work surface 211 by the
inwardly facing surface 2110 and the flange 2111. The flange 2111
has a lower surface 2112. The first chamber 213 is generally
defined below the aperture 212 and the plane of the upper work
surface 211 and is delimited by interior facing surfaces of the
sidewalls 210 and the upper work surface 211. The groove 214 is
generally defined in the plane of the upper work surface 211 and is
communicative with the aperture 212.
[0025] The second body 22 is disposable within the first chamber
213 of the first body 21 and includes a main body 220 formed to
define an inlet 221 and having an upper surface 222 and a
peripheral ridge 223. The peripheral ridge 223 runs along a
periphery of the upper surface 222 such that the peripheral ridge
223 and a central section of the upper surface 222 define a second
chamber 224, which is fluidly communicative with the inlet 221.
[0026] The flexible membrane 30 may be formed of rubberized
material and is disposable to seal the second chamber 224. The
flexible membrane 30 includes a first section 31 and a second
section 32 and has a thickness that is substantially similar to a
distance between the interior facing surface of the upper work
surface 211 of the first body 21 and the peripheral ridge 223 of
the second body 22. The first section 31 is interposable and
tightly fittable between the first and second bodies 21 and 22 and,
in particular, between the interior facing surface of the upper
work surface 211 of the first body 21 and the peripheral ridge 223
of the second body 22. The second section 32 is defined within the
first section 31 and is thus disposable to seal or in some cases
hermetically seal the second chamber 224. With the second chamber
224 pressurized at atmospheric pressure, an upper surface 310 of
the flexible membrane 30 may be substantially coplanar with a plane
of the interior facing surface of the upper work surface 211.
[0027] The mobile plate 40 is disposable within the first chamber
213 of the first body 21 and in the aperture 212. The mobile plate
40 includes a body having an exterior facing surface 410 and a
footer 411. The footer 411 extends outwardly from a lower portion
of the exterior facing surface 410 and has an upper flange surface
412. The lower surface 2112 of the flange 2111 of the upper work
surface 21 and the upper flange surface 412 overlap with one
another such that, as the mobile plate 40 is raised, the upper
flange surface 412 contacts the lower surface 2112 to thereby limit
an upward motion of the mobile plate 40.
[0028] The mobile plate 40 is disposable in contact with the upper
surface 310 of the flexible membrane 30. As such, the mobile plate
40 effectively floats on the flexible membrane 30 and can be
maneuvered or re-oriented in accordance with a condition of the
flexible membrane 30.
[0029] The mobile plate 40 further includes an uppermost surface
413 on which, e.g., the second component 3 of FIG. 1 is removably
attachable by way of, for instance, vacuum pressure. This vacuum
pressure may be generated by a vacuum system 42 including a hose
420 that extends along the groove 214. In addition, adhesive may be
dispensed on the uppermost surface 413 to increase a degree of
bonding of the second component 3 to the uppermost surface 413.
[0030] The pressure regulating system 50 is coupled to the second
body 22 and is configured to regulate a pressure within the second
chamber 224 that is sufficient to deform the flexible membrane 30
toward the mobile plate 40 or to permit deforming of the flexible
membrane 30 in the opposite direction. In accordance with
embodiments, the pressure regulating system 50 may include a hose
51, which is coupled to the inlet to thereby direct pressurizing
fluid into the second chamber 224, and, in some cases, a controller
52. Where the pressure regulating system 50 includes the controller
52, the controller 52 monitors a pressure within the second chamber
224 and increases or decreases the pressure in accordance with a
compressive force between the first and second components 2 and 3
and cure characteristics of any adhesive used between the first and
second components 2 and 3. In the case where the pressure within
the second chamber 224 is sufficient to deform the flexible
membrane 30 toward the mobile plate 40, the pressure has to be
limited to such a level that the compressive force between the
first and second components 2 and 3 will be sufficient to push down
the upper flange surface 412 of the mobile plate 40 off its resting
position against the lower surface 2112 of the upper work surface
211 of the first body 21.
[0031] With reference to FIGS. 5A and 5B, in one embodiment, the
flexible characteristic of the flexible membrane 30 and the
pressure within the second chamber 224 permits a certain degree of
rotational or translational movement of the mobile plate 40 within
the aperture 212. In such cases, as the first and second components
2 and 3 are brought together in a non-parallel orientation (see
FIG. 5A), the flexible membrane 30 deforms downwardly, which can in
some cases result in reducing a volume of the second chamber 224.
This causes the mobile plate 40 to rotate to therefore bring the
first and second components 2 and 3 into a more parallel
orientation.
[0032] As shown in FIGS. 6A-6E an alternative operation of the
bondline control fixture 10 as described above will now be
described. In this embodiment, the second chamber 224 is
pressurized to inflate the flexible membrane 30. The flexible
membrane 30 is thus deformed or curved upwardly and to create a
tangential contact between the upper surface 310 of the flexible
membrane 30 and the mobile plate 40. Such tangential contact
permits a certain degree of rotational or translational movement of
the mobile plate 40 within the aperture 212 to the extent permitted
by the interference between the upper flange surface 412 of the
mobile plate 40 and the lower surface 2112 of the upper work
surface 211 (which has the secondary result in an increased contact
area between the mobile plate 40 and the flexible membrane 30).
[0033] At an initial time, as shown in FIG. 6A, the first and
second components 2 and 3 are brought toward one another with the
second chamber 224 un-pressurized and the flexible member 30
un-deformed. Then, as shown in FIG. 6B, the second chamber 224 may
be pressurized such that the mobile plate 40 will be urged upwardly
until the upper flange surface 412 rests against the lower surface
2112. Next, as shown in FIG. 6C, the first and second components 2
and 3 are brought together in the Z-direction and in a non-parallel
relative orientation.
[0034] As the first and second components 2 and 3 continue to come
into contact, as shown in FIGS. 6D and 6E, the compressive forces
between the first and second components 2 and 3 exceed the pressure
generated within the second chamber 224 and the mobile plate 40 is
forced downwardly such that the upper flange surface 412 recedes
from the lower surface 2112. In this condition, the mobile plate 40
is effectively rotated along the upper surface 310 of the flexible
membrane 30, which will be non-uniformly deformed. This rotation of
the mobile plate 40 brings the first and second components 2 and 3
into a parallel relative orientation without requiring any
micro-adjustments being made by the first component maneuvering
device (i.e., the picker arm 4 of FIG. 1). Once the parallel
relative orientation is achieved with the first and second
components 2 and 3 in contact, the adhesive used between the first
and second components 2 and 3 can be cured.
[0035] For instance, an optically transparent UV-curable adhesive
could be used. The optical transparence should be to the wavelength
of the light signals coupled between component 2 and 3 and is
important to minimize optical coupling loss. A refractive index of
the adhesive should be below a refractive index of a waveguide on
component 2. A UV-curable adhesive could improve throughput via
fast tacking or cure compared with a thermally cured adhesive.
[0036] It will be appreciated that the second chamber 224 can be
pressurized prior to assembly to a level not forcing plate 40 to
fully rest upper flange surface 412 on lower surface 2112. The
contact between 412 and 2112 prior to assembly can full, partial or
none. The amount of pressure in chamber 224 depends on the desired
assembly force and the resulting desired assembly pressure between
component 2 and 3. The desired assembly pressure is a function of
the viscosity of the adhesive and the stiffness and mechanical
robustness of components 2 and 3. The larger the adhesive viscosity
and the larger the component stiffness and mechanical robustness,
the larger the desired assembly force.
[0037] With reference to FIG. 7, an active bondline control fixture
100 is provided for affixing the first and second components 2 and
3. The active bondline control fixture 100 includes similar
features as those of the bondline control fixture 10 described
above and a detailed description of those features will be omitted.
The active bondline control fixture 100 includes a base 110, which
is fixable relative to a first component maneuvering device (i.e.,
the picker arm of FIG. 1) and which defines an aperture 111 and a
groove 112 in an upper work surface 113 thereof and a chamber 114,
a mobile plate 120 and an actively controllable actuation system
130. The second component 3 is removably attachable to the mobile
plate 120 by way of vacuum pressure and is movably (i.e., rotatably
or translationally) disposable at least partly in the aperture 111.
The actively controllable actuation system 130 is configured to
adjust an attitude of the mobile plate 120 relative to the base 110
in accordance with a degree of parallelism between the first and
second components 2 and 3.
[0038] In accordance with embodiments, the actively controllable
actuation system 130 includes a plurality of actuators 131. The
actuators 131 are disposed within the chamber 114 and are
respectively coupled at first ends thereof to the base 110 and at
second ends thereof to local portions 121 of the mobile plate 120.
The actuators 131 may be provided as linear actuators that can
extend or retract in the Z-direction and thus may be configured to
adjust distances between the base 110 and the local portions 121 of
the mobile plate 120. In accordance with embodiments, the actuators
131 may be provided in a group of three actuators 131 that are
arranged in a triangular formation. As such, by increasing or
decreasing the distances between the base 110 and the local
portions 121, the actuators 131 can control an attitude of the
mobile plate 120 relative to the base 110.
[0039] As shown in FIG. 7, the actively controllable actuation
system 130 may include a controller 132 that is respectively
coupled to each of the actuators 131 and a sensor 133. The sensor
133 may be disposed to sense the degree of parallelism between the
first and second components 2 and 3 and may be provided as a
pressure sensor at each of the actuators 131. The sensor 133 could
thus identify when the first and second components 2 and 3 are
brought together in a non-parallel relative orientation since
initial contact between the non-parallel first and second
components 2 and 3 will read as a high pressure input at the
actuator 131 proximate to a "low" side of the first component 2 and
as a low or zero pressure input at the actuator 131 proximate to
the "high" side.
[0040] The controller 132 may include a processing unit 1320
disposed in signal communication with the sensor 132, a memory unit
1321 and servo controllers 1322 that are respectively coupled to
each of the actuators 131. The memory unit may have executable
instructions stored thereon, which, when actuated, cause the
processing unit to receive pressure readings from the sensor 132 of
the actuators 131, to determine from those pressure readings a
degree of non-parallelism between the first and second components 2
and 3, to determine a corrective action needed to increase the
degree of parallelism and issue commands to the servo controllers
in accordance with the determined corrective action. The servo
controllers may then control the actuators 131 and, in particular,
may control the actuator 131 associated with the high pressure
reading to retract. In so doing, the controller 132 will thereby
lower the mobile plate 120 at the "low" side and to in turn
increase the degree of parallelism between the first and second
components 2 and 3.
[0041] In accordance with aspects, a method of passively or
actively affixing the first and second components 2 and 3 to one
another is provided. The method includes supporting the mobile
plate 40/120 on the base 20/110, which is fixable relative to a
first component maneuvering device (i.e., the arm picker 4 of FIG.
1), removably attaching the second component 3 to the mobile plate
40/120, maneuvering the first component 2 toward the second
component 3 with the first component maneuvering device and
passively or actively manipulating the mobile plate 40/120 to
increase a degree of parallelism between the first and second
components 2 and 3. In accordance with embodiments, the passive
manipulating may include deforming the flexible membrane 30 whereas
the active manipulating may include adjusting the distance between
the mobile plate 120 and the base 110.
[0042] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one more other features, integers,
steps, operations, element components, and/or groups thereof.
[0043] The corresponding structures, materials, acts, and
equivalents of all means or step plus function elements in the
claims below are intended to include any structure, material, or
act for performing the function in combination with other claimed
elements as specifically claimed. The description of the present
invention has been presented for purposes of illustration and
description, but is not intended to be exhaustive or limited to the
invention in the form disclosed. Many modifications and variations
will be apparent to those of ordinary skill in the art without
departing from the scope and spirit of the invention. The
embodiment was chosen and described in order to best explain the
principles of the invention and the practical application, and to
enable others of ordinary skill in the art to understand the
invention for various embodiments with various modifications as are
suited to the particular use contemplated.
[0044] While the preferred embodiment to the invention had been
described, it will be understood that those skilled in the art,
both now and in the future, may make various improvements and
enhancements which fall within the scope of the claims which
follow. These claims should be construed to maintain the proper
protection for the invention first described.
* * * * *